import random
kl = []
kll = []
li = [1, 2, 3, 4, 5, 6, 7, 8, 9]
for i in range(97, 123):
    # b = random.randint(97,122)
    b = [chr(i)]
    li = li + b
for i in range(65, 91):
    b = [chr(i)]
    li = li + b
# for j in range(4):
#     print(random.choice(li),end='')

while True:
    kl = random.choices(li, k=4)
    for i in range(10):
        for j in kl:
            if j == i:
                for i in range(97, 123):
                    b = chr(i)
                    for j in kl:
                        if j == b:
                            # print(kl)
                            # break
                            for i in range(65, 91):
                                c = chr(i)
                                for j in kl:
                                    if j == c:
                                        kll = kl
                                        break
    else:
        if kll != []:
            for j in kll:
                print(j,end='')
            break


